fix: cast sub as str

[botanical]

Issue

Link to relevant GitHub issue

What?

• Cast sub as str and remove default None since that will be cast as str which we want to avoid

  >>> token = { }
  >>> x = token.get("sub", None)
  >>> str(x)
  'None'
  >>> exit()

Why?

• We were receiving this error when trying to kick off a /dataset/publish/ workflow 1 validation error for Ingestion\ncreated_by\n str type expected (type=type_error.str) and, to be safe, we are casting sub as str

Testing?

• Locally deployed on dev and ran /dataset/publish/ successfully https://4e76fa52-1de6-41a5-b364-691fb1cc69f4.c18.us-west-2.airflow.amazonaws.com/dags/veda_ingest_raster/graph?run_id=0767fd24-461d-481f-85eb-2ebb4662d144_617296f2-18e1-4711-9961-8a542bb8958b_0&execution_date=2024-05-02+19%3A54%3A13.422305%2B00%3A00